Pre-treatment of timber in a controlled factory environment.
Whether with a flame retardant or preservative product, factory application ensures a measured improvement in performance with the minimum of environmental impact or human exposure.
There are three proven and widely available industrial processes:
Wood Modification
Vacuum Pressure Impregnation
A penetrating process used for both flame retardant and preservative treatment application to solid timber and wood based products.
Integral to Manufacture
WPA approved flame retardants can be incorporated to particle board and medium density fibreboard (MDF) as an integral part of production (achieving the performance set out in relevant fire test Classification Report).
PROCESSES ARE SPECIFIC TO MANUFACTURER.
Factory applied Coatings
WPA approved flame retardants can be surface applied in a factory under third party quality assured processes (achieving the performance set out in relevant fire test Classification Report).
PROCESSES ARE SPECIFIC TO MANUFACTURER.
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Treatment facilities usually consist of a large cylindrical treatment vessel, multiple storage tanks and a rail track, all enclosed in a bunded area to contain any spillages.
Preservative Treatment
There are two main processes: low pressure (or double vacuum) and high pressure.
Low pressure treatments are typically for timbers specified for Use Classes 1 – 3 coated. The predominantly water-based treatment provides an effective ‘envelope’ protection around the timber.
High pressure treatment is particularly effective for Use Class 3 and 4 applications, especially for in ground contact as higher levels of protection can be achieved.
Timber Treatment Plant Control Systems
Most treatment formulations are supplied as concentrate which need to be added to either water or another liquid to create a 'solution'. The way they are mixed depends on the formulation, timber species, component and treatment class required. Specific solution loading guides published by the formulation manufacturers and used by plant operators should be quality checked on a regular basis.
Plant control software systems significantly enhance quality control and data reporting around the treatment operation. Such systems can be obtained from formulation manufacturers or plant suppliers.
Timber Treatment Incising Technologies
Incising technologies are increasingly utilised for preservative impregnation of high risk post components - small even incisions provide channels for deeper penetration of the preservative formulation.
Specialised systems for use either as stand alone or as part of the whole production line can be designed and engineered to suit a sawmill's particular set-up. There are machines to incise either round or flat sided posts.
We have two WPA members who are both engineering experts in their field of plant and system design and manufacture: Tweddle Engineering (Timber Preservation Technologies), based in the UK and Wood Treatment Technology (WTT) based in Denmark.
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WPA Resource Centre
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All of our resources are free to view and download. Please contact us if you have questions about any aspect of wood protection specification, quality assurance or application good practice.